Bi4Ti3O12铁电材料的合成及结构分析

用溶胶－凝胶技术合成了到铋微粉和薄膜。研究了前驱体溶液的ｐＨ值对溶胶，凝胶，粉体特性的影响以及钛酸铋材料的晶相转变过程。研究表明，ｐＨ＝３．５的前驱体溶液制得的粉体和薄膜的性能较好，其于凝胶在晶化过程中出现三个中间相：Ｂｉ２Ｔｉ４Ｏ１１相，ＢｉＴｉ３Ｏｘ相和Ｂｉ２Ｔｉ２Ｏ７焦绿石相；在８５０℃粉体全部转为单斜晶系的Ｂｉ４Ｔｉ３Ｏ１２结构。     

金属有机物分解法制备钛酸铅薄膜

用金属有机物分解法制备了钛酸铅薄膜。研究了成膜的技术条件。一次甩胶可以获得厚约0.1μm均匀、无开裂、无针孔的薄膜,较厚的膜可通过多次甩胶得到。X射线衍射证实,经700℃热处理后,膜呈现四方钙钛矿的单相结构。Rutherford背散射表明,即使在多次甩胶制得的膜中,组份的厚度分布也是均匀的。     

PZT薄膜的MOD制备及形成机理研究

采用金属有机物热分解（ＭＯＤ）工艺在Ｐｔ／Ｔｉ／ＳｉＯ２／Ｓｉ衬底上制备锆钛酸铅（ＰＺＴ）薄膜。ＸＲＤ分析显示薄结晶状态良好,无焦绿石相存在。ＡＥＳ测量表明：薄膜成分沿膜厚均匀分布,膜中无碳存在,表面不富含铅。分析了薄膜的形成机理,安性地解释了晶粒的生长过程。     

液态源雾化化学沉积法制备(Pb,La)TiO3薄膜

研究了在Pt/Ti/SiO2 /Si基片上用液态源雾化化学沉积法制备镧钛酸铅 [(Pb ,La)TiO3,PLT]薄膜的工艺 ,并分析了各种因素对其相结构的影响。采用金属有机物热分解工艺的先体溶液 ,在沉积阶段 ,用超声波将先体溶液雾化 ,产生微米级的汽雾 ,由载气 (Ar)引入沉积室进行沉积 ,并在沉积室进行预热处理。重复上述过程 ,直到膜厚达到要求 ,再进行退火处理得到均匀、致密的薄膜。此工艺各项参数如下 :沉积前沉积室内气压为 4× 10 - 3Pa ;沉积时沉积室内气压为 8× 10 3～ 9× 10 3Pa ,沉积时基片温度为 2 0～ 2 5℃ ;预处理温度为 30 0℃ ;最佳热处理温度为 60 0℃ ;超声雾化器工作频率为 1.7MHz;薄膜沉积速率为 3nm/min。XRD和SEM图分析说明 ,制备的铁电薄膜具有钙钛矿结构     

矿化剂对水热合成钛酸铋纳米粉体的影响

以分析纯五水合硝酸铋和四氯化钛为原料配制前驱物,调节pH为8～9,用水热法制备钛酸铋纳米粉体,以XRD分析了不同矿化剂的种类和浓度对钛酸铋粉体物相组成的影响.结果表明:以氢氧化钾为矿化剂比氨水利于钛酸铋晶相的形成,当矿化剂氢氧化钾的浓度为1.0～2.0 mol/L时,可以生成单一的正交相钛酸铋纳米粉体,而以氨水为矿化剂得不到钛酸铋物相.以TEM和SEM观察了钛酸铋纳米粉体的微观形貌.TEM结果表明:钛酸铋晶粒的宽度在30 nm左右,长度大于100 nm.SEM测试表明粉体颗粒之间有一定的团聚.     

非水解溶胶–凝胶法制备钛酸铝薄膜及其抗熔盐腐蚀性能

采用非水解溶胶–凝胶工艺,以无水三氯化铝和四氯化钛为前驱体,乙醇为氧供体,环保型高沸点二元酸酯混合物AGSE为溶剂,四丁基溴化铵为稳定剂,在碳化硅基片上制备出均匀、致密的钛酸铝薄膜。借助差热–热重、X射线衍射、场发射扫描电镜和扫描电镜等研究了钛酸铝干凝胶热处理过程中的相变化、钛酸铝薄膜的晶相组成、显微结构及其抗硝酸钠熔体腐蚀性能。结果表明:在750℃低温制备的钛酸铝薄膜晶粒约为10nm,薄膜具有良好的抗硝酸钠熔体腐蚀性能;热处理温度提高到1350℃后,钛酸铝薄膜的晶粒增大至120nm左右,晶界面积急剧减小,无定形相消失,钛酸铝薄膜的抗硝酸钠熔体侵蚀性能大大提高。     

La3+掺杂TiO2薄膜制备及其电致变色特性研究

基于提高TiO2薄膜的光学属性和着色效率,以钛酸四丁酯和氧化镧为主要原料,采用溶胶-凝胶法,在ITO玻璃表面制备La3+掺杂TiO2薄膜.通过XRD、SEM、EDS、TG-DTA等手段对制备La3+掺杂TiO2凝胶粉末进行表征,使用电化学工作站CHI660E和紫外-可见光分光光度计UV-5500PC对La3+掺杂TiO2薄膜的电致变色性能进行测试.结果表明:凝胶在加热的过程中发生一系列的物理和化学反应,且当温度升高至400 ℃时,系统达到相对热稳定状态.经600℃热处理,La3+掺杂TiO2转化为金红石相.外加电压为-2V时,薄膜显示为深蓝色,反向施压至+2V时,蓝色褪去.金红石相TiO2无定形程度随La3+掺入量增加而提高,对应其着色效率提高.La3掺杂TiO2薄膜在可见光范围内透过率均在70％ ～ 80％,光学性能良好.     

共沉淀法制备Bi3.25La0.75Ti3O12纳米粉体

用硝酸铋、硝酸镧和钛酸四丁酯为原料，硝酸、无水乙醇和去离子水为溶剂，氨水为沉淀剂，采用共沉淀法合成了单相铋层状钙钛矿结构Bi3.25La0．75Ti3O12(BLT)纳米粉体。用DTA／TG和XRD研究了BLT前驱体的热行为和晶相转化过程，用场致发射扫描电子显微镜观察了BLT粉体的颗粒形貌和大小的变化。结果表明：共沉淀前驱体溶液的配制过程中，硝酸铋水解生成的硝酸氧铋不利于层状钙钛矿结构BLT相的合成。利用浓度较高的硝酸作溶剂，可以防止硝酸铋的水解，采用氨基共沉淀法直接合成出了单一相的BLT纳米粉体，在煅烧过程中，未出现Bi2Ti2O3焦绿石相。700℃煅烧2h合成的BLT粉体颗粒不大于100nm，颗粒间结合疏松，具有良好的分散性。     

溶胶-凝胶法制备LiNbO3薄膜的研究

对近年来有关溶液－凝胶法制备LiNbO3薄膜的研究进行了较详细的论述，分析讨论了在溶胶－凝胶法制备了LiNbO3薄膜过程中，各主要因素对LiNbO3薄膜制备的影响，简要地介绍了LiNbO3薄膜的一些性能。研究结果表明，目前可以用溶胶－凝胶法在蓝宝石及LiTaO3等基板（基板的晶格参数与LiNbO3的晶格参数失配较小）上制备出有光学应用的LiNbO3薄膜，制膜的热处理温度通常在500℃左右，讨论了溶胶－凝胶法制备LiNbO3薄膜过程中存在的主要问题、发展前景有今后的研究方向。     

低温燃烧合成铬酸镧纳米粉体的结构特性

用低温燃烧合成法合成了铬酸镧纳米粉体.X射线衍射和扫描电镜分析的结果表明:粉体由La1-xCaxCrO3和少量的LaCrO4,La2CrO6和有机物组成.合成过程形成的中间相LaCrO4是凝胶分解反应不完全的结果,La2CrO6的形成与阳离子未完全络合有关.燃烧后的产物呈薄膜状,厚度约80 nm;高温煅烧时薄膜状产物中的有机物挥发和LaCrO4,La2CrO6分解导致薄膜发生破碎,并形成粒径约80 nm的粉体.煅烧后粉体尺寸均匀,但部分颗粒间存在硬团聚.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。